Hornresp

@eddy
It seems the upper drawing is somewhat different then the sketch below.

Upper: driver working on ported volumes, each duct going into a third volume, which also is ported.

Lower: Same as above, with the addition of a second port in compliance one.

This second port - when tuned differently to the first one, should act as a second Helmholtz Resonator on the chamber "compliance #1"... This should act like a "double tuned bassreflex", regarding this part of the whole construct - I messed around with systems like that a long time ago - wasn't worth it, to much "mess" - but who knows, now tools, now opportunities
 
Hi Fred,

is there any potential use in adding a port as below where the green line points ?

See my previous post - a fourth port is not going to happen :).

or would it create severe cancellation effects?

If you experiment with the BP7 option, you will find that cancellation due to the interconnecting port tube 3 is not an issue.

Kind regards,

David
 

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Hi David,

It's seems me that there should be something interesting around actually implemented BP7 with 2 port outside : It should be interesting to be able in BP wizard to show both port output curves and not only the sum.
I would be really interested too if there would be a way in BP wizard to switch port by port to a simplier model without resonnance taken into acount, to be able to see wich port is responsable of wich resonnance. Actually i cheat reducing 10 times cross-sectional area of a port and reducing it lengh to compensate, but it reduce total volume too so it's not that much a good way to cheat ^^

I have the feeling that you should be prone to add those features.


Kind regards,

damien
 
Hi Damien,

It should be interesting to be able in BP wizard to show both port output curves and not only the sum.

I'll think about it :).

I would be really interested too if there would be a way in BP wizard to switch port by port to a simplier model without resonnance taken into acount, to be able to see wich port is responsable of wich resonnance.

That would introduce yet another layer of complexity, that I can well do without. It's not going to happen!

When all else fails, there is always AkAbak...

Kind regards,

David
 
How to adjust driver offset--on a transmission line design.

Hi kebailey,

The driver offset is specified by L12.

(If the Loudspeaker Wizard is used and the S2 slider set to Auto by double-clicking on the 'S2 Manual' label, the driver can be moved up and down the transmission line by adjusting the L12 slider, without changing the overall transmission line profile).

Kind regards,

David
 

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Hi David,
Just like to say I have been playing with your program for some time now and feel now that I understand how to use it reasonably well, I do have a couple of questions I would like to ask and maybe a suggestion that might be of interest. First of all, thanks for providing your time and expertise in such a difficult subject that 90% of us wouldn’t even know how to start or make.
Suggestion if possible, when you are trying to fine tune your horn / design would it be of benefit to do so with all possible pages to be displayed so you are able to see the improvements you make, one of the most important I think is the power conversion efficiency (percent) but you have to close this menu to be able to make changes, maybe in the corner a little tick box for the pages you wish to display when you click to recalculate on the input page, maybe this isn’t as important as I think but maybe it is, love to hear what you think.
I’m trying to design some horns for 12’’ to 18’’ speakers up to 120Hz and up to 500Hz and in the process was thinking that instead of just 1 speaker for each horn, it might be better to fit 2 or more for hi power density per horn size, Question being what level of compression is ok and not affect the sound quality and how far down the horn would this pressure need to travel before expanding.
Last Question are round horns better, even when they take up far more space
I hope you have the time to answer my questions
Kind regards
 
Hi clf,

when you are trying to fine tune your horn / design would it be of benefit to do so with all possible pages to be displayed

See point 2 in Post #9256: https://www.diyaudio.com/forums/subwoofers/119854-hornresp-926.html#post5725276

what level of compression is ok and not affect the sound quality and how far down the horn would this pressure need to travel before expanding.

It really depends on the output power level, but as a general rule for a bass horn, a compression ratio not exceeding 4:1 should be okay for all but the most extreme cases. It is not possible to give a definitive answer to the second part of your question - obviously though, the lower the expansion rate near the throat, the higher the distortion.

are round horns better

It depends on what you are trying to achieve. For example, there is little scope for independently controlling the horizontal and vertical directivities of a round horn, whereas this is possible to some degree with a rectangular cross-section horn.

For bass horns, a rectangular cross-section is fine.

Kind regards,

David
 
Could optimize feature be implemented?

Hi 1hiep0,

The problem is what to optimise. All loudspeaker designs are compromised one way or another. It is really up to the Hornresp user to decide which parameter(s) to optimise depending upon the outcome they wish to achieve. The slider controls in the real-time Loudspeaker Wizard are provided to hopefully make this task a little easier. Realistically though, this is about as far as it is practically possible to go.

Kind regards,

David
 
Agreed, with the wizard, you don't need to know hardly anything about the fundamentals of speaker design. I was rather surprised that some early 'freehand', totally 'off the wall' TH alignments by [admittedly clueless] others that conformed to no acoustically derived theory I'm aware of proved better overall in some cases than the best of what traditional speaker/horn theory predicted!

GM
 
Hi David,
Thanks for answering my questions
Multiple menus, it seems this change would require extensive work and time to change so I understand your reluctance to do so.
Level of compression, the horns will be used in a DJ / Band setup so I’m looking to maximize the output but still want it to sound really good, judging by what you say 4:1 compression is the max, would less compression say 2:1 sound better
If the Compression & Expansion of the horn all happened within the first quarter or half of the horn, would that provide a good sound quality and dB output
Are Round Horns Better, I know that round horns take up a lot more room and don’t forget about the construction difficulties but forget about that for a moment, is there any benefit in sound quality and output level, maybe less reflection back when folding the expanding horn
I was considering constructing the first 2/3 as round and as the horn expands to about 600mm, begin to make it rectangular as it expands to 800mm x 1000mm with an area of say 8000 or maybe larger say 10000
The drivers will be 2 x 18’’ or what is required, I’m trying to get high output and good quality for the size of sub’s (better than you can buy)
Kind regards
 
Hornresp Update 5030-190714

Hi Everyone,

CHANGE 1

A ninth order band pass enclosure loudspeaker option has been added. Attachments 1 and 2 refer.

CHANGE 2

An externally-vented port tube in a band pass, DBR or ABC system can now be replaced by one or more passive radiators.

To specify a passive radiator in a band pass, DBR or ABC system, press the Ctrl key and double-click the Fr label while in edit mode. Press the Ctrl key and double-click the Sp1 label to specify multiple passive radiators. Double-click the Sp1 to Sp9 label to restore the default Fr label.

To replace an externally-vented port tube with a specified passive radiator, double-click on the Ap1, Ap2 or Ap3 label for that port. The label changes to Mma and the Mma text box value becomes the mass in grams added to each passive radiator diaphragm.

To select the alternative externally-vented port in a BP6P, BP7, BP9 or ABC system, double click on the Ap label for that other port.

To remove a passive radiator and restore the port tube, double-click on the Mma label in edit mode.

Attachments 3, 4 and 5 refer.

CHANGE 3

When activated by double-clicking on a chart, the green fundamental resonance marker in the band pass enclosure loudspeaker wizard is now also shown on the port velocity charts. Attachment 6 refers.

CHANGE 4

Individual acoustic power output charts have been added to the band pass enclosure loudspeaker wizard. Attachment 7 refers.

BUG FIX

Changes made in the band pass wizard to BP5 chamber 3 and port 3 values, and to BP7 port 3 values, were not being saved back to the input parameters window. This has now been fixed.

Kind regards,

David
 

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I’m trying to get high output and good quality for the size of sub’s

Hi clf,

If the bass horns are to be used in a DJ / Band environment, and assuming that the input power is not unrealistically high, I would be surprised if you could discern any meaningful difference in sound quality by using a compression ratio of 2:1 rather than 4:1, or by using an initial round rather than rectangular, horn cross-section.

Others with more practical experience in such matters might like to comment also, particularly if they have a view different to mine :).

Kind regards,

David